RFR: 8378675: PPC64: increase instruction cache line size

[Martin Doerr]

On Wed, 25 Feb 2026 13:37:31 GMT, David Briemann <dbriemann at openjdk.org> wrote:

> Set the instruction cache line size for Power to 128 bytes.
> 
> Add functions to retrieve the data cache line size and instruction cache line size from the system (AIX & Linux).

LGTM. Thanks for cleaning up the data cache related code as well. Please update the Copyright headers.

src/hotspot/os/linux/os_linux.cpp line 5386:

> 5384: 
> 5385: int os::get_dcache_line_size() {
> 5386:   int size = sysconf(_SC_LEVEL1_DCACHE_LINESIZE);

A comment would be nice: The query returns 0 on some old systems.

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PR Review: https://git.openjdk.org/jdk/pull/29918#pullrequestreview-3854403976
PR Review Comment: https://git.openjdk.org/jdk/pull/29918#discussion_r2853173585